Manifold sheets coated with lactone and related chromogenous compounds and reactive phenolics and method of marking



Apnl 5, 1966 N. w. FARNHAM ETAL 3,244,549

MANIFOLD SHEETS COATED WITH LACTONE AND RELATED CHROMOGENOUS COMPOUNDSAND REACTIVE PHENOLICS AND METHOD OF MARKING Filed Aug. 31, 1961 BASEWEB, ORIGINAL TRANSFER COATING ON BACK CONTAINING BIS (p-AMINOPHENYL)-PHTHALAN OR --PHTHALIDE TRIPHENYLMETHANE DERIVATIVE ADHERENT COATING 0NFACE CONTAINING SUBSTITUTED PHENOL AS COLOR DEVELOPER BASE WEB,DUPLICATEI TRANSFER COATING ON BACK (OPTIONALIJ INVENTORS. EARL J.GOSNELL NORMAN W. FARNHAM Maw I.

ATTORNEY United States Patent 3,244,549 MANIFQLD SHEETS COATED WITHLA'CTUNE AND RELATED CEHXOMGGENUUS COMPOUNDS AND REAQTIVE PHENOL'ICS ANDMETHOD OF MARKING Norman W. Farnham, Webster, and Earl .l. Gosuell,Irondequoit, N.Y., assignors to Burroughs Corporation, Detroit, Mich, acorporation of Michigan Filed Aug. 31, 1961, Ser- No. 135,294 32 Claims.(Cl. 117-362) This invention relates to arrangements and methods forproducing dark colored marks from colorless materials, which ordinarilyappear White, or from materials which are only lightly colored. Thesematerials usually are incorporated in coatings on webs, the coatingsconveniently being on paper rolls, ribbons, or sheets. As used in thepresent specification and in the appended claims, both achromaticcolors, that is, grays and black, and chromatic colors are included;dark colored materials may be dark gray or black; or they may bechromatic colors likewise of low brilliance, such as dark blues, greens,purples, reds, and browns whether of low or high saturation, or evenvivid colors of high saturation and high brilliance, such as brightblues, greens, and reds. All of these colors are distinguished markedlyfrom colorless materials, or from lightly colored materials having whiteor light gray colors or having pastel shades of high brilliance but lowsatura tion.

The use of dyes and pigments in making multiple copies ofcorrespondence, business documents, multiple forms and records, and thelike always has been a source of some annoyance due to the tendency ofthe colored materials to smudge and to soil the skin and clothing of theuser. A common example is carbon paper; another is the use of dyes onthe master sheets or in the printing solutions employed in officeduplicating systems. Considerable success has been achieved in makingcarbon paper less susceptible to casual transfer of the coloring agents,as by covering the transfer layer with a thin wax coating, or by bindinga colored transfer vehicle within a layer from which only substantialpressure causes it to be eX truded, but smudging and soiling still canoccur during handling. Likewise some duplicating systems have been madecleaner by using diazo substances having little coloring or stainingpower until brought into contact with a 'diazo coupler, but diflicultyin providing proper conditions -for the diazo coupler reaction haslimited their use, and the colored marks are less intense than thoseproduced by the standard duplicating master sheets using the highlycolored triphenylmethane dyes.

Another system proposed early in the development of the art involves thetransfer by writing or typing pressures of one color reagent from asheet or coating, which replaces a carbon sheet, to the face of aduplicate sheet carrying a complementary color reagent. Use of materialssuch as ferric sulfate on one surface and tannic acid on the other wereproposed, such that deposits of a dark colored compound of the twomaterials are formed -where the reagents are brought together on theduplicate surface. In the absence of the second reagent, no amount ofhandling can cause smudging. Shortcomings such as unwanted colorformation on the treated surfaces during storage or casual handling, orinsufficient speed of formation, contrast, and stability of the coloredmarks, or the necessity of maintaining adequate moistness or otherreaction environment at the marking surface, have kept such systemsusing many types of color reagents from extensive use.

Marking systems of this general type have been proposed which utilize ascolor-producing or chromogenous compounds the le-uco, or simpleamino-substituted tri- 3,244,549 Patented Apr. 5, 1966 phenylmethane,substances such as leuco-malachite green, crystal violet, and ethylviolet, or the corresponding paraa-mino-substituted triphenylrnethylcarbino'ls. From the standpoints of stability of both the chromogenouscompounds and the color-activating materials used therewith, and ofcontrol in developing the colored forms, it has been found advantageousin some marking or image-duplicating systems to utilize the lactoneforms, which are p-aminosubstituted diphenylphthalides, corresponding tothe above-mentioned leuco forms, or the lactones or colorless bases ofthe rhodamine dyes.

It is known that lactone materials of these types, dissolved in an oilyliquid, may be brought into contact with particles of an inorganicmaterial such as 'attapulgite, halloysite, magnesium trisilicate,calcium silicate, or basic aluminum silicate to produce dark coloredproducts. Weak acids such as acetic acid and tartaric acid also havebeen suggested for use with the lactone color-forming compounds todevelop dark colored products, but in practice the clay-like materialsor other inorganic solids such as those mentioned above have been usedfor this purpose. In addition to acetic and tartaric acids, dilutedstronger acids also have been suggested generally for this purpose, butwithout naming any specific acids, strengths, or dilutions, and there isno indication that any specific inorganic acids or any other carboxylicacids have been found to be desirable or particularly suitable. TheWeaker inorganic acids, such as boric acid, also appear to have littleif any efficacy in producing dark colored products from the chromogenouslactone compounds. Thus it is neither necessary nor especially probablethat a material having the chemical constitution and dissociationproperties recognized as characteristic of acids Will be desirable orparticularly suitable for such a purpose. Even when using the inorganiccolor-developing materials mentioned above, the solid colored productslose much or all of their color in the presence of various polarsolvents and their vapors, notably Water; they tend to deteriorate withage and are noticeably unstable to irradiation as from sunlight orfluorescent lamps.

It is an object of the present invention, therefore, to provide noveland improved web coatings, methods of marking and duplicating orotherwise developing dark colored materials, and such materialsthemselves, which avoid one or more of the disadvantages of the priorart.

It is another object of this invention to provide new coatingarrangements and associated color-developing systems for use withlactone and related chromogenous compounds, so as to provide novel,spirit-soluble and oilsoluble, dark colored materials or marks havinggenerally improved characteristics such as color intensity, speed ofcolor development, insensitivity to moisture, and resistance toradiation, oxidizing agents, and other environmental influences whichtend to cause deterioration of the colored product.

It is a further object of this invention to provide a manifolded setarrangement, utilizing a novel combination of colorless or lightlycolored smudge-proof materials, for producing one or more copies bytransfer of color-generating substances from the back surface of eachsheet in the set to the face of the next lower sheet to form marks orcharacters of improved high contrast and durability on the lower sheetor sheets immediately upon writing or printing on the top sheet.

It is still another object of this invention to provide new and improvedmethods of developing dark colored ma terials from chromogenouscompounds, useful in particular for producing marks on a substrate, andfor making duplicate images by new and improved modifications of thespirit-duplicating process.

In accordance with the invention, an article of manuo facture isprovided in the form of a web carrying a substituted phenol havingsubstituent radicals selected from the group consisting of a singlesubstituent which is one of the alkyl, allyl, halo, halo-substitutedalkyl, cycloalkyl, phenyl, halo-substituted phenyl, alkyl substitutedphenyl, biphenylyl, =benzyl, and alpha-alkylbenzyl radicals, of any twosubstituent radicals and of any three substituent radicals includedamong such single substituents except when two of the two or threesubstituent radicals are in the 2,6-positions relative to the phenolichydroxyl group, of the tetramethyl and tctrahalo radicals, of any of thesubstituent radicals and such groups of two, three, and four substituentradicals with a second hydroxyl radical also on the phenol, of thepara-nitro radical, and of the pentamethyl and pentahalo radicals, theweb being adapted for utilizing such substituted phenol to develop adark colored material by its action on a colorless or lightly coloredchromogenous compound which includes as its major functional arrangementthe molecular structure the web has an adherent coating which comprisessuch substituted phenol bonded to the web but accessible to othermaterials coming into contact with portions of the coating; otherwisespecified, the web carries such substituted phenol, evenly distributedin amounts of from 0.2 to 8 grams per 1,000 square inches of websurface. In a modification the adherent coating comprises a filmformingmaterial containing, as a finely dispersed phase, a substituted phenolhaving the above-mentioned action on such chromogenous compounds.Alternatively the web carries the specified substituted phenoltransferable upon local impact from the web to a surface contiguoustherewith, where contact may be made with the chromogenous compound onsuch contiguous surface.

In accordance with a feature of the invention, a manifolded setcomprises a first base web having on one side a transfer coatingcontaining the above-identified chromogenous compound, which istransferable upon impact from the coating to a surface contiguoustherewith, and a second base web carrying on at least one active surfaceone of the substituted phenols identified above, the first and secondwebs being maintained disposed together in face to face relationshipwith the transfer coating in contiguity with the active surface,whereby, upon such impact in localized areas, a dark colored material isproduced locally by the action of the substituted phenol carried on theactive surface in opening the bond from the central methane carbon atomto the heterocyclic oxygen atom to permit quinonoid resonance in thechromogenous compound transferred to the active surface. In accordancewith a more specific feature of the invention, the transfer coating ismade up of a film-forming material which is rupturable upon impact andwhich contains as a finely dispersed phase numerous cells of a liquidvehicle carrying the chromogenous compound. In a related but broaderaspect of the invention, either one of the two constituentsthechromogenous compound and the substituted phen01is selected anddissolved in the liquid vehicle present asthe numerous cells in thetransfer coating on the first base web, while the other of theseconstituents is bonded to the second web in an adherent coating thereonbut accessible to the first-selected con stituent when it comes intocontact with portions of the adherent coating.

In accordance with a method feature of the invention,

the method of developing dark colored materials from chromogenouscompounds comprises bringing the aforementioned chromogenous compoundinto reaction contact with the substituted phenol. In the method ofmarking on a substrate, the chromogenous compound is brought intocontact, in areas on the substrate where marking is desired, with thesubstituted phenol to produce marks in such areas of a dark coloredmaterial formed by the action of the substituted phenol on thechromogenous compound. The invention also encompasses the newcomposition of matter comprising the dark colored substance obtained byintimate contact of the substituted phenol with the colorless or lightlycolored chromogenous compound.

In a method of duplicating, in accordance with the invention, twocolorless or lightly colored substances are provided, these substancesbeing the aforementioned ichromogenous compound and the substitutedphenol, and the method then comprises forming, on the surface of amaster sheet, deposits of a preselected one of these two substances inareas representing an image to be duplicated but with mirror-reversedimage elements. Thereafter a solution of the remaining one of the twosubstances in a solvent liquid is applied to the surface of a duplicatesheet, and this duplicate sheet surface, wetted with the solvent liquidcontaining that remaining one of the two substances, is pressed againstthe master sheet surface to effect transfer by the solvent liquid ofportions of the image-representing deposits of the preselected one ofthe two substances from the master sheet surface to the duplicate sheetsurface in areas thereon representing the image, whereby a duplicateimage is formed on the duplicate sheet surface of dark colored materialproduced by the action of the substituted phenol on the chromogenouscompound. In a modification of the method of duplicating, in accordancewith the invention, the remaining one of the two substances is carriedat all times on the surface of the duplicate sheet, and a liquid whichis a solvent for the preselected one of the two substances is applied tothat surface, which then is pressed, thus wetted, against the mastersheet surface to cause portions of the preselected one of the twosubstances deposited thereon to dissolve in the liquid and to betransferred into contact with the remaining one of the two substances,carried on the duplicate sheet surface, in the areas thereonrepresenting the image, whereby a duplicate image in the dark coloredmaterial is formed on the duplicate sheet surface.

For a better understanding of the present invention, together with otherand further objects thereof, reference is had to the followingdescription taken in connection with the accompanying drawing, and itsscope will be pointed out in the appended claims.

The single figure of the drawing shows in exploded view two manifoldingunits, suitable for use together in face to face contiguity in amanifolded set with or without additional similar manifolding units.These units are shown as coated webs, illustrated in cross section withthe thicknesses of the base webs and of the coatings on the web surfacesgreatly exaggerated for convenience of illustration.

The manifolded set illustrated comprises a base web 11 having on oneside a transfer coating 12, containing as a coating constituent asubstance which interacts with a second substance to generate a coloredmaterial, and which is transferable upon impact from the coating 12 to asurface contiguous therewith. The coating 12 may be simply the solidsubstance to be transferred, bonded to the web 11 by a solid adhesive orhinder of a Waxy or resinous material which may be dislodged underpressure from the web surface, but preferably a liquid vehicle isprovided, dispersed throughout a solid film, which carries the substanceto be transferred, as will be discussed in greater detail hereinbelow.Thus the first base web 11 preferably has the coating 12 made up of afilm-forming material which is rupturable upon impact and which containsas a finely dispersed phase numerous cells of a solvent liquid vehicle.Another base web 13 also is provided, having an adherent coating 14 onone side, being the side nearer the web 11 and its coating 12. Duringuse, as will be discussed, the two webs are maintained disposed togetherin face to face relationship. The adherent coating 14 carries theaforementioned second substance such that the two individual coatingconstituents, although each is colorless or only lightly colored,together form upon intimate contact with each other a dark coloredproduct. One of these coating constituents is a colorless or lightlycolored chromogenous compoundof a type identified hereinbelow. The othercoating constituent is a phenolic substance which may be classified as asubstituted phenol and which also will be identified more particularlyhereinbelow.

Accordingly, in one embodiment of the invention a manifolded set isarranged with the phenolic substance in the transfer coating 12. The web11 then carries, transferable therefrom upon local impact to a surfacecontiguous therewith, the selected phenolic substance, so that the webis adapted, upon such impact and transfer of portions of the substancelocally to the contiguous surface of the Web 13, for contact thereon ofthe portions so transferred with the chromogenous compound to develop adark colored material by the action of the substance so transferred onthe chromogenous compound. However, one advantage of these phenolicsubstances, as color developers for the class of chromogenous compoundsinvolved, is the solubility of the phenolic substance in many vehicles,including nonvolatile liquids having physical properties well suited foruse as vehicles in color-producing and marking systems; color-developingsubstances such as the clay-like inorganic substances recommended byprior art practice lack such solubility. Thus the transfer coating 12may be made up of a film-forming material such as casein, gelatin, acellulose derivative, or polyvinyl alcohol, applied as a hydrophilicaqueous composition containing an oily liquid vehicle emulsifiedtherein, so that the dried film is rupturable upon impact and containsas a finely dispersed phase numerous microscopic droplets or cells ofthe liquid vehicle carrying the phenolic substance dissolved therein.The vehicle may be any one of numerous suitable nonvolatile solventvehicles, such as castor oil, sperm oil, a chlorinated phenyl ether, orbenzyl butyl phthalate. In this embodiment the other color-reactivematerial, or chromogenous compound, is bonded to the web 13 in theadherent coating 14 by a cementitious material.

Because of a degree of water solubility, a few of the phenolic materialsmay have a tendency to be absorbed from the solvent vehicle dropletsinto the film-forming material and so reach the exposed surface of thecoating without any rupture of the film. This may be avoided byencapsulating the minute droplets of the vehicle containing the phenolicsubstance in thin, pressure-rupturable shells of Water-imperviousmaterial before the vehicle is mixed into the aqueous film former.Applying the mixture to the web then provides a clean transfer coating.

With respect to a few phenolic substances, usually in impure or admixedforms, they are in a liquid state at or near room temperature and can beemulsified in a filmforming composition, with the use of little or nosolvent material, to form a liquid dispersed phase. In another aspect, aweb with a transfer coating containing a phenolic substance may take theform of a fabric n'bbon impregnated with ribbon-inking oils which carrythe substance to be transferred. Such a ribbon may be used in atypewriter for applying the transferable substance to the surface of asheet carrying the chromogenous compound or other color-reactivematerial. Dark colored marks or characters then are formed on the sheetby impact of the types through the ribbon, even though the ribbon andthe sheet surface are white in color prior to use.

On the other hand, some systems for developing dark colored marks areoperative with a transfer ribbon or sheet containing the solidtransferable material in a simple frangible transfer medium of, forexample, solid or plasticized wax.

In a different arrangement in accordance with the invention, the firstbase web 11 in the manifolded set has a transfer coating 12 on the backcontaining the specified chromogenous compound, which in most cases maybe viewed as a compound related to, or a derivative of, triphenylmethanebut having a heterocyclic ring including the methane carbon atom, morespecifically a 1,l-bis(paminophenyl)phthalan compound or a3,3-bis(p-aminophenyl)phthalide compound, usually with substituents. Thesecond base web 13 in this embodiment of the invention then carries thephenolic substance, preferably evenly distributed in amounts of from 0.2to 8 grams per 1,000 square inches of web surface. When it is of asuitable material, the web or its surface regions on one side may beimpregnated by dissolving the phenolic substance in a volatile solvent,applying the solution to the web, and drying. The phenolic substanceaccordingly is carried on at least one active surface of the web.Preferably the web carries on only one active face an adherent coatingcontaining the phenolic substance as the color developer. Some of thephenolic substances may be made to adhere as a coating to most paper orfilm Web materials Without the use of an adhesive or film-formingsubstance. Usually, however, it is desirable to include an inert binderin this coating. The coating nevertheless readily may contain enoughphenolic substance to make up much more than half of its weight, and inany case the web should have on one side an adherent coating comprisingthe phenolic substance bonded to the web in an amount equal to at leastten percent of the weight of the coating. For this purpose the adherentcoating conveniently comprises a film-forming material containing thephenolic compound as a separate, finely dispersed phase but accessibleto other materials coming into contact with portions of the coating, sothat the coated web is adapted for developing dark colored material at aportion of the coating when a colorless or lightly colored chromogenouscompound of the type described herein comes into contact with thatportion of the coating. Whether the phenolic substance is carried on aweb in a transfer coating or in an adherent coating, the web is adaptedfor the production of dark colored material by contact of the phenolicsubstance on the web with the chromogenous compound.

The use in large proportions of an impervious adhesive material whichwould coat or cover most of the phenolic substance in an adherentcoating would render the coating practically ineffective by preventingcontact of much of the developer substance with any chromogenouscompound brought onto the surface of the coating. Assuming that thecoating is sumciently pervious so that the developer material therein isaccessible, one means for bringing the chromogenous compound intocontact with portions of the coating to develop colored material is toincorporate in or on the same coating numerous very small capsulescontaining the chromogenous compound dissolved in a solvent liquid. Withthis arrangement local impact or pressure on the coating causes thecapsules to break locally, bringing about contact of the tWo materialsWithin the single coating to develop the dark colored marks. Desirablemarking sensitivities and color-free unmarked surfaces are more easilyobtained, however, when the coated web carrying the developer materialis used as a manifolding unit in a manifolded set, as illustrated forexample in the drawing. Of course, the developer substance in thecoating 14 would be accessible to chromogenous materials coming intocontact with the coating if substantial portions of the developersubstance are exposed at the top of the coating, even though theadhesive which joins the lower portions of the developer substance tothe face of the web 13 is itself impervious. If the chrornogenouscompound is carried by a liquid vehicle which permits the chromogenouscompound to penetrate to the developer substance in the coating 14, itobviously would not be necessary that the developer substance in thecoating be accessible to all materials which might reach the coating.

For applying the phenolic substance to the web 13- as an adherentcoating 14, in which the phenolic substance is accessible tochromogenous materials coming into contact with the coated face of theweb, many filmforming or cementing materials are available for use asbonding agents. Various agents have different tendencies to coat thephenolic substance and so partially obstruct access thereto of thechromogenous material, but the proportion of phenolic substance tocementing material on a dry basis ordinarily can be made high enough toinsure entirely sufficient access while permitting adequate bonding.When the coating procedure involves dispersion of the phenolic substancein an aqueous film-forming composition, there may be a tendency withsome phenolic substances to dissolve in the coating composition, but,upon evaporation of the liquid medium during drying, any such dissolvedphenolic substance usually crystallizes out as solid portions which areaccessible to the chromogenous material while being bonded to the web.

A preferred binder material for the phenolic substance is a film formerwhich can be applied to the web surface as a latex. A synthetic latexconveniently may be used, and ordinarily the phenolic substance, andconventional dispersing and foam-inhibiting agents when desired, arereadily compatible with such a latex. A polybutadienestyrene latexadvantageously may be used, such as one having in the water vehicle 48%by weight of resin solids formed from monomers with a 2:1butadiene:styrene ratio. An example of this coating composition follows,as applied for instance to a paper or film web such as a 12 poundsulfite bond paper, then dried:

Other polybutadiene-styrene latices having larger or smallerbutadiene-styrene ratios with suitable dispersing agents may be used inthis formulation, and other filmforming latices also may be substitutedfor the polybutadiene-styrene latex, usually with a lower proportion ofphenolic compound to latex solids. Neutral or inert pigments serve tomake the adherent coating whiter and more opaque and frequently aredesirable in amounts of roughly a tenth of the coating weight on a drybasis. Titanium dioxide pigment has been used, for which zinc oxide,zinc sulfide, or zirconium dioxide, as other examples, may besubstituted. These pigments, at least in such quantities, have nonoticeable effect on the colordeveloping activity of the adherentcoating; in fact, if the phenolic substance were to be omitted from thecoating, leaving only such an inert pigment, the coating would have nocolor-developing utility. For the dispersing agent there was used in thecomposition given above a solution of the sodium salt ofnaphthalene-sulfonic acid condensed with formaldehyde; a number ofdispersing agents of this and related types are available to the art.When an antifoaming agent is indicated, small amounts of conventionalmaterials such as the silicones, fatty acid esters, petroleumdistillates, and the higher aliphatic alcohols may be used in the latexcomposition.

I A coating composition such as the one just described may be applied soas to obtain usefiul dried coatings in a very broad range of thicknessand weights. A coating roughly 0.0002 inch thick of this driedcomposition, having a coating weight of about 4 grams per 1,000 squareinches and a weight of the phenolic compound of about 3 grams per 1,000square inches, usually gives excellent results. While a range of about1.5 to 4 grams of the phenolic compound per 1,000 square inches of websurface is preferred, coatings giving useful results ordinarily may haveamounts of from 0.2 to 8 grams per 1,000 square inches. Smaller amountsin extremely thin coatings ordinarily would not provide adequate colordeveloping action, while larger amounts in relatively thick coatingsordinarily would not be justified by any improvement in color-developingactivity. The dry coating of the example given above has a high ratio offive times as much phenolic compound as resin binder by weight, butentirely useful coatings can be obtained when the inert bondingmaterials weigh several times as much as the phenolic substance in thecoating. Thus it appears that amounts of the phenolic substance in thecoating equal to well over 10% of the dry coating weight and within theaforementioned weight limits per unit web area may be obtained readily.

Reference now will be made to the chemical structure of the phenolicsubstances included or utilized in the several embodiments of thepresent invention. As mentioned above, these phenolic substances may beclassified as substituted phenols. More specifically, the substitutedphenol has substituent radicals selected from the group consisting:

Of a single substituent which is one of the (a) alkyl, (b) allyl, (c)halo, (d) halo-substituted alkyl, (e) cycloalkyl, P y (g)halo-substituted phenyl, (h) alkyl-substituted phenyl, (i) biphenylyl,(j) benzyl, and (k) alpha-alkylbenzyl radicals; Of

(1) any two substituent radicals and of (m) any three substitutentradicals included among the single substituents (ak), except when two ofthese two (1) or three (m) substituent radicals are in the 2.6-positionsrelative to the phenolic hyd roxyl p; Of the (n) .tetramethyl and (o)tetrahalo radicals; Of any (p) of these substituent radicals (a-k) andgroups of (q) two substituent radicals (l), (1) three substituentradicals (m), and (s) four substituent radicals (n-o), but with a secondhydroxyl radical also on the phenol; Of the (t) para-nitro radical; andOf the (u) pentamethyl and (v) pentahalo radicals.

Obviously there is available a large variety of sub- 'stituted phenolswhich have one of the substituents or groups of substituents listed inthe above tabulation. In

colored marks obtained when contact is effected with a givenchromogenous compound.

1 1 Benzylphen0l' HCH H H o1 ('11 a-phenyloeresol a-(3,4-diehlorophenyl)-p-cresol 15 m zn a-phenyl-p-eresol (k)a-Alkylbenzylphenol OH I E o-a-methylbenzylphenol The above-mentionedmonoalkyl-substituted phenols, and also the monohalo phenols, are amongthe most highly active materials for developing the color of thechromogenous compounds utilized in accordance with the presentinvention. The p tert butylphenol and p tert pentylphenol, althoughexcellent color developers, are somewhat less active than the otherslisted. Each of the phenols shown as having the nonyl and dodecyl groupsrepresents color is developed quickly by contact of these liquidphenolic developers with the color reagent in solid form or in liquidsolution. If it should be desired to use a system in which the developercompound is retained on a copy sheet, possibly for long periods ofstorage prior to use in marking or duplicating, there may be a problemwith some compounds, such as the cresols and also the xylenols mentionedbelow, whichtend to be volatile and to evaporate or sublime, whetherthey are in liquid or solid form and in some cases even though theyremain solid at temperatures substantially above any ordinary roomtemperatures. Coating or encapsulation and adhesion techniques known tothe art may be used to retain these compounds on a base web withnegligible loss by evaporation under normal conditions. However, the useof alkyl substituents which give solid phenols of lower volatility maybe desirable. In the case of the liquid dodecylphenol, for example, itmay be dissolved in another liquid for use as a marking fluid or as partof an emulsion-type coating, or it' may be emulsified without dilutionin a film-forming composition used in forming a transfer coating.

Referring to the allylphenols, it will be appreciated that compoundshaving equivalent color-developing properties are obtained when theallyl radical is replaced, for example, by a 2-chloroallyl or2-bromoallyl radical, or by a butenyl radical or the l-methylallyl orZ-methylallyl radical.

The (monocycloalkyl) phenols shown are among the less active colordevelopers, although they are operative to develop colored marks, ando-cyclohexylphenol, for ex ample, can be quite useful with manychromogenous compounds.

In this connection, o-phenylphenol has been found to have moderate togood color-developing abilities, while p-phenylphenol is relativelyquite poor, developing marks only slowly, or marks which are quite lowin intensity, with many chromogenous compounds. When using a materialhaving a color-developing activity as low as that of p-phenylphenol, itmay be necessary to use diligently the ordinary skill of one wellpracticed in the art in choosing a suitable solvent for. some of thechromogenous compounds, and otherwise in arranging the conditions underwhich the color-forming compounds are brought into contact with thephenolic developer compounds, in order to obtain markings which are notvery faint. On the other hand, 2-chloro-4-phenylphenol, mentionedhereinbelow, gives colored marks considerably darker than the averagemarks obtained with a randomly selected phenolic developer substance ofthe types under consideration, and this ortho-substituted p-phenylphenolmay be made to produce very dark marks immediately when brought intocontact with, forexample, some of the diphenylphthalide chromogenoussubstances. 4

The inclusion of small groups such as methyl or halo groups on the ringof a phenyl or benzyl substituent ordinarily gives a compound havingessentially equivalent color-developing utility. In addition to thehalophenyl and alkylphenyl substituents illustrated,a-(3,4-dichlorophenyl)-p-cresol is included as equivalent to theu-phenylp-cresol. 1

The phenolic compounds shown above exemplify with considerable varietythe substituted phenols having substituent radicals consisting of asingle substituent which is one of the alkyl, allyl, halo,halo-substituted alkyl, cycloalkyl, phenyl, halo-substituted phenyl,alkyl-substituted phenyl, biphenylyl, benzyLand alpha-alkylbenzylradicals.

Among the poly-substituted phenols may be mentioned the followingphenols with two and three substituents:

(l) Phenol with two substituents (l) Phenol with twosubstituents-Continued on on O01 001 4- ter t-butyl-Z-chlorophenolI2-ehloro-4-dode cylpheuol $11 OH C 1 Br 2-chloro-4-phenylphen0l2-bromo4-phenylphenol 4-chlorma-phenylo-cresol 2,4-diphenylphenol '(m)Phenol with three substituents on. i

' CHa 2, 3, 5-trimet-hylphenol 2, 4, fi-trichlorophenol(isopseudoeumenol) i-chloro-B, 5-xylenol Again a considerable range ofeffectiveness is observed. For example, the disubstituted compoundsshown above which include 'chloro substituents tend to be developers ofgood to excellent strength, as does the 2-allyl-p-creso1.

fi-chlorothymol "Thus, 'the two dichlorophenols give good results, asdoes 4-chloro-m-cresol. Particularly recommended are the compounds2-chloro-4-phenylphenol and 4-chloro-a-phenyl-o-cresol, which providestrong colordeveloping action with high stability and W volatility. Itis notable that thymol is one of the least active of the developersshown, while on the contrary the trisubstituted compound 6-chloro-thymolhas particular efficacy as a developer. As with 2,4-dichlorophenol, the2,4,5-trichlorophenol is a developer of very high activity, which istypical of the chloro-swbstituted phenols, whether monosubstituted orpoly-substituted. The other two trisubstituted phenols shown providerelatively low eliectiveness as developers, although they can producedark-colored forms of acceptable intensity, especially with the moreactive chromogenous compounds having intensely dark colored forms.

The disubstituted and trisubstituted phenolic compounds shown aboveprovide varied examples of the substituted phenols having any twosubstituent radicals and any three substituent radicals included amongthe single substituents,

listed :herein above inconnection with the monosubstituted phenolsillustrated, except when "two of the two :or three 'substituent radicalsare in the 2g6-posi'tions relative to the phenolic hydroxyl group. Ithas been discotvered that .5 the color-developing activity of :thesubstituted phenols thus excepted is so it'ee'ble orundependable thattheir use is not recommended. Examples ofrthe gl-atter 'compounds are2,6-diclrloropheno-l OH 10 I 15 which rapidly develops color in contactwith p-aminosubstituted 3,3-diphenylphthalide chromogenous compoundsonly to ha ve the color disappear almost immediately;2,4,6-trichlorophenol OH o1-@ d1 which is only weakly active; andd-chloro-o-cresol on Cl-OGH:

and 4-cyclohexyl-Zgd dichlorophenol (ll-O01 Hz? (EH3 Hag C 2 0. H2

neither of which exhibits substantial color-developing ability.

Also of particular interest are certain other substituted phenols,poly-substituted with one or two exceptions, including those mentionedbelow:

(n) 'Tetramethylphenol HaC CH3 2,3,5;6,-tetrarnethylphenol (durenol),(0) T etrahtaloph eno-l 2,3,4,G-tetrachlorophenol These substitutedphenols with tetramethyl and tetrahalo radicals in general exhibitmoderate color-developing activity.

In another category of substituted phenols, the substituentradicalsspecifically, the radicals in the sub- 15 stituted phenols whichhave the above-listed single substituents and which have the variousgroups of two and three substituents, as previously discussed, as wellas the tetra-substituted radicals just mentioned-are present in (p)Dilzydric phenol with one substituent OH (|)H O ]OH i i l 01 (E4-pheny1pyro- 4-ch1ororephenylhydroquinone catechol sorcinol (q)Dihydric phenol with two substituents Cl '4,6-dichlorcresorcinol (r)Dihydric phenol with three substituents H 0- CH3 trimethylhydroquinoneDihydriophenol with four substituents tetrachlorohydroquiucne Of thedihydric compounds shown, the phenylhydroquinone and the4-chlororesorcinol and 4,6-dichlororesorcinol exhibit color-developingactivity well above the average, while that of the others is somewhatless than the average.

The substituted phenols having as substituent radicals the para-nitroradical, developing fair to good colors in properly designed systems,and the pentamethyl and pentahalo radicals include primarily thefollowing:

(t) Nitrophenol p nitrophenol T6 (u) Pentamethylphenol H C CHa H30 CH lCH3 pentamethylphenol (v) Pentohalophenol O H OH 01 Cl Br Br 01 Cl Br BrI Cl Br pentachlorophenol pentabromophenol The pentasubstituted phenolsalso have fair to good color-developing properties, whilepentachlorophenol in particular has proved quite useful as a colordeveloper of high activity with many chromogenous compounds.

Notice has been taken hereinabove of the desirability, for the variousembodiments of the present invention, of the monohalophenols, of anumber of dichlorophenols and trichlorophenols, wherein bromo or otherhalo radicals might replace the chloro substituents, and of thetetrahalophenols, pentabromophenol, and the pentachlorophenol justmentioned. These compounds are representative of the category ofsubstituted phenols having at least one halo substituent; as noted abovewith respect to the disubstituted and trisubstituted phenols in general,there should be excepted from this category such substituted phenolshaving two halo substituents and such substituted phenols having threehalo substituents when two of the two or three substituents are in the2,6-posi tions relative to the phenolic hydroxyl group.

Reference'should :be made, moreover, to the sodium and potassiumderivatives of the substituted phenols discussed hereinabove, that is,to the corresponding phenoxides, sometimes referred to as phenates. Asregards the compositions, arrangements, and methods of the presentinvention, these phenoxides are in general the equivalents of thesubstituted phenols from which they may be derived. There is a tendencyfor the phenoxide derivatives to exhibit slightly lower color-activatingpotential than the corresponding phenols. However, such phenoxidescorresponding to a great many of the substituted potassium2,4,5-trich1orophenoxide I sodlutn 2,3,4,6-tetraehl0ropheuoxide sodiumpentaehlorophenoxide Manifolded set arrangements which include webscarrying the phenolic compounds discussed hereinabove, especially theface-coated webs carrying the phenolic colordeveloping substanceadherent thereto, now will be described in greater detail, andparticular reference then will be made to the variety of chromogenousmaterials suitable for inclusion in the arrangements and methodsutilizing the phenolic color-activating substances.

The web or sheet 13 described hereinabove, having on one side anadherent coating 14 carrying a phenolic substance as describedhereinabove, conveniently. is included, in an embodiment of the presentinvention, as the lower or second base web or sheet in a manifolded setwhich also comprises the upper or first base Web or sheet 11. In thisarrangement the firstbase web 11 has on one side the transfer coating 12made up of a filmforming material containing a colorless or lightlycolored chromogenous compound which is transferable upon impact fromthat coating to a surface contiguous therewith. This chromogenouscompound includes as its major functional arrangement the molecularstructure having a p-amino-substituted triphenylmethane group with abond from the methane carbon atom thereof to the heterocyclic oxygenatom. It will be understood that substituents may be present on thebenzene rings in this compound provided that the illustrated structureremains the effective major functional arrangement in the compound.

The first and second webs 11 and 13 are maintained disposed together inface to face relationship, as suggested by the bracket at the left ofthe drawing, with their respective transfer and adherent coatings 12 and14 in contiguity with each other, whereby, upon impact in localizedareas, a dark colored material is produced locally by the action of themany small particles of the phenolic substance, carried by the adherentcoating 14, in opening the bond from the methane carbon atom to theheterocyclic oxygen atom to permit quinonoid resonance in the smallmasses of the chromogenous compound which are transferred locally to thecontiguous adherent coating from the transfer coating 12 as a result ofthe impact. For producing simultaneously an original and one copy sheetby use of a typewriter, for example, or by directwriting with pen,pencil, or stylus, the web 11 advantageously serves as the original andthe face-coated web 13 serves as the duplicate. These two coatedmanifolding units 11 and 13 and other pairs like them may be fastenedtogether in successive sets in a pad, or they may simply be laid oneover the other on a writing surface, or held together on the platen of atypewriter. Typing or writing impact, or other printing or markingpressure, on the face of 18 the sheet 11 causes localized rupture of theback coat,- ing 12, releasing and transferring some of the chromogenouscompound from that coating locally to the contiguous surface of theadherent face coating 14. Of course, it is possible to cause a similartransfer by impact applied to the back of the web 13.

It is possible to incorporate the generally light-colored chromogenousmaterial, of the type described above and in the solid state, into aback coating 12 of waxy or thermoplastic film-forming material, whichmay be trans ferred from the base web 11 upon impact to deposit some ofthe solid chromogenous material on a surface, such as that of thecoating 14, carrying a color-activating material. Production of thedarker colored form occurs best, however, if the chromogenous substanceis dispersed or preferably dissolved in a liquid, permitting intimatecontact of the molecules of the chromogenous substance with thecolor-developing material. It is possible to provide some of thissolvent on the surface carrying the color-developing material.Preferably, however, the film-forming material of the back coating 12,which is rupturable upon impact or other localized pressure, contains asa finely dispersed phase numerous cells, or microscopic droplets, of aliquid vehicle carrying the colorless or lightly colored chromogenouscompound. The cell walls may be simply boundary regions Within thecontinuous film or may consist of a third encapsulating material. A lowvapor pressure, lipophilic (oil-loving), nonpolar or mildly polar liquidsolvent vehicle advantageous is used, such as Ibenzyl butyl phthalate,benzyl salicylate, phenyl ether or halogenated phenyl ethers,chlorinated biphenyl, partially hydrogenated .terphenyls, laurylbromide, butyl oleate, or other such vehicles or mixtures thereof, inwhich the chromogenous compound is dissolved.

A solution of from about 1% to 10% by weight of the chromogenouscompound in such a solvent vehicle may be prepared, for example, andthen emulsified in a conventional aqueous film-forming material such aspolyvinyl alcohol in colloidal solution, or such as a colloidal aqueoussolution of casein, gelatin, or the like. The resulting emulsion of thelipophilic solvent in the hydrophilic film former is coated on the backsurface of the base Web 11, which may be a strip or sheet made of paperor other fibrous material or of a plastic film base, and then is driedto form the coating 12 containing numerous liquid cells of thewater-insoluble solvent vehicle carrying, dissolved therein, thechromogenous substance. Use of a suitable emulsion results in suchliquid cells being finely dispersed throughout the solid film, formed bydrying the hydrophilic film former, which makes up the continuous phasein the coating 12. The dried coating 12 may be about 0.001 inch thick.The ratio of the solvent vehicle containingthe chromogenous compound tothe dried filmforrning materials in the coating advantageously may be inthe approximate range of 1:1 to 1.5 1.

Marking pressure or impact then releases the chromogenous material fromthose of the .tiny cells in the coating 12 which occupy the areasimmediately beneath the areas of impact on the original printing orwriting surface. The above-disclosed phenolic substance in thecontiguous coating 14 is adherent to the web 13 but is accessible. tomaterials applied to the surface of this coating, so that adequatecontact occurs of the chromogenous compound, transferred from thecoating 12, with the phenolic substance, and the dark-colored form ofthe chromogenous compound thus is produced to provide dark marks in theduplicate image areas on the coating 14.

It will be understood that, if desired, a coating 15 may be formed onthe 'back surface of the duplicate web 13 in just the same manner as theback coating 12 is formed on the original web 11. With this optionalback coating 15 on the Web 13, one or more additional duplicate coatedwebs, identical with the coated web 13, may be manifolded beneath theweb 13, permitting simultaneous production of triplicate andquadruplicate copies. In fact, most of the phenolic substances utilizedin accordance with the present invention, when applied in face coatingssuch as the coating 14 described above, themselves provide good originalprinting or writing surfaces, so that a sheet such as the sheet 13, whenprovided with the back coating 15 as well as the face coating 14, mayserve either as an original sheet or as a duplicate sheet in amanifolded set or stack. Thus identical paper sheets, each having whiteor light colored face and back coatings acceptable as ordinary papersurfaces to most users, may be manifolded in sets of two or more, orseveral sheets may be manifolded in which the face coating may beomitted from the top sheet only and the back coating may be omitted fromthe bottom sheet only. No smudging or soiling of the paper sheets or ofthe users hands occurs in ordinary usage, and dark colored material isformed only in the duplicate image areas by the aforementioned action ofthe phenolic developer material on the almost colorless or white, orrather lightly colored, chromogenous material.

More generally described, the manifolded set comprises a first base webhaving on one side a transfer coating made up of a film-forming materialwhich is rupturable upon impact and which contains as a finely dispersedphase numerous droplet-like cells of the solvent liquid vehicle, and asecond base web having on one side an adherent coating, in a manifoldingarrangement which maintains these first and second webs disposedtogether in face to face relationship with the respective transfer andadherent coatings in contiguity. with each other. Two coatingconstituents. are provided, one in theform of the chromogenous compoundwhich includes the major functional arrangement with the molecularstructure shown above, and another coating constituent in the form of acolor-activating phenolic substance. One of the coating constituents isdissolved in the solvent liquid vehicle present in the numerous cells inthe transfer coating on the first base web, and the other of the coatingconstituents is bonded to the second web in the adherent coating thereonbut is accessible to other materials coming into contact with portionsof that adherent coating.

An advantage of the color-activating phenolic substances utilized inaccordance with the present invention is that, if desired, each of themcan be dissolved readily in certain organic liquids recognized assolvents therefor. Thus the phenolic substance may be dissolved in theliquid cells in the transfer coating on the first web, and thechromogenous compound may be bonded to the contiguous surface of thesecond web. Of course, if the phenolic substance is a liquid at ordinaryambient temperatures, it may be emulsified directly in the aqueousfilm-forming solution used in forming the transfer coating, so that thephenolic substance serves in a sense as its own liquid solvent. However,it usually is preferred to adopt the reverse system, described moreparticularly hereinabove, and dissolve the chromogenous compound in theliquid dispersed in minute cells in the back coating 12 on the web 11,while bonding the color-activating substance to the web 13 in theadherent face coating 14.

In either case, upon local impact and rupture of the transfer coating,the release of the liquid vehicle containing one coating constituentfrom some of the liquid cells onto the contiguous adherent coatingcarrying the other coating constituent effects contact between the twocoating constituents to produce a dark colored material by the action ofthe phenolic substance on the chromogenous compound. The mechanism ofthis action need not be demonstrated in showing the operation of thearrangements and methods of the present invention. Nevertheless, itcommonly is theorized, in the study of colored substances having anaminotriphenylmethane structure, that absorption or reflection of lightselectively in various portions of the visible spectrum is associatedwith the presence of the quinonoid structure in one of thep-ami-nophenyl groups, as may be represented in the structural having adouble bond from the methane carbon atom to a quinonoid-modifiedaminophenyl group, and that this quinonoid structure shifts throughresonance from one to another of the aminophenyl groups. This structuralformula will be recognized as being related to the molecular structureof the major functional arrangement in the chromogenous compounddescribed hereinabove. Presumably contact of the color-activatingmaterial with the chromogenous compound results in loss of an electronfrom the latter, promoting the quinonoid structure having a double bondfrom an aminophenyl group to the methane carbon atom, with opening ofthe bond from the methane carbon atom to the heterocyclic oxygen atom inthe chromogenous compound. The precise or complete structure of thedark-colored material, produced by the action of a phenoliccolor-activating material on these chromogenous compounds, is not known,and the hypothetical formula for the quinonoid form, given above, is notintended to be a complete structural representation. Whatever the exactmechanism may be, it seems reasonable in view of the present state ofthe art to assume that the color-activating substance acts byeffectively opening a bond from the methane carbon atom withestablishment of the double bond arrangement associated with an adjacentquinonoid group, permitting quinonoid resonance in the chromogenouscompound.

Reference now will be made again to the chromogenous compound, before itis acted upon by the color-activating substance, having the majorfunctional arrangement involving the molecular structure, shownhereinabove, with a p-amino-su'bstituted triphenylmethane group and aheterocyclic ring; the methane carbon atom of the triphenylmethane grouphas a bond to the hetero oxygen atom, which in turn is bonded to acarbon atom afiixed to one of the phenyl groups in the ortho position,This molecular structure is included with the minimum of substituents inthe compound l,1-bis(p-aminophenyl)phthalan. The latter compound isrepresented by the structural formula 1' 1" i m N The colorless 'orlightly colored chromogenous compound preferably is selected from thegroup consisting of the last-mentioned compound, the 2',2-epoxy, 3-oxo,and 2',2-epoxy-3-oxo derivatives thereof, bifunctional derivatives ofeach of these compounds having a second heterocyclic ring fused to the5,6 side of the benzene nucleus and similarly carrying extracyclicsubstituents the same as those carried by the carbon atoms designated 1and 3, the S-amino derivatives of the 1,1-bis (p-aminophenyl)phthalanand of the above-mentioned epoxy and x0 derivatives thereof, andN-substituted derivatives of each of the compounds here listed in whicheach individual substituent for an amino hydrogen atom is selected fromthe group consisting of an alkyl radical of not more than four carbonatoms, the henzyl radical, and the phenyl radical.

Each of these compounds can be seen to include as its major functionalarrangement the molecular structure set forth hereinabove, with hydrogenatoms or appropriate substituents on the amino nitrogen atoms and on theavailable heterocyclic carbon atom, and with or without othersubstituents, such as the epoxy linkage and the third p-amino radical,or such as the bifunctional arrangement involving a secondbis(p-aminophenyl)methyl group and a second heterocyclic ring fused withthe 5,6 side of the benzene nucleus. The N-substituted derivatives ofthe several compounds listed above are by far the most important membersof this group of chromogenous compounds. Examples of the chromogenoussubstances having particular utility in connection with the presentinvention will be given now.

Turning first to the 1,1-bis(p-aminophenyl)phthalan itself, itsstructural formula may be redrawn as follows:

It may be used, preferably dissolved in a lipophilic solvent, to developa violet color when brought into contact with a phenoliccolor-activating or developer substance.

However, it is preferred to provide related chromogenous compounds inwhich at least one of the two hydrogen atoms in each amino radical isreplaced by a substituent tending to increase the color intensity ormodify the hue of the dark-colored material which may be formed from thechrornogenous compound. Thus the corresponding N monosubstitutedcompound 1,1 bis(p ethylaminophenyl)phthalan develops a greenish bluecolor of greater intensity, while the N-disubstituted compound 1,1-bis(p-dimethylaminophenyl)phthalan forms a still more intensely coloredquinonoid form with a green, or somewhat bluish green, hue. The compound1,1-bis(p-diethylaminophenyl)phthalan produces an intense, greendark-colored form in contact with the phenolic developer substances, andsimilar dark-colored forms may be obtained, for example, from similarcompounds having diisopropylaminophenyl and dibutylaminophenyl groups.These compounds illustrate the selection of one or more of theindividual N-substituents, that is, substituents for the amino hydrogenatoms, from the alkyl radicals of not more than four carbon atoms. Ingeneral, more intense and more stable colors may be obtained when thereare substituents replacing most or all of the amino hydrogen atoms.Moreover, instead of these N-alkyl-substituted compounds, thebenzyl-substituted compounds 1,1-bis(p-benzylaminophenyl)phthalan and1,1 bis(p dibenzylaminophenyl) phthalan may be used to obtain darkgreenish blue quinonoid forms. As an example of an alternativederivative, having N-phenyl substitutents, there may be mentioned 1,1bis(p N methylanilinophenyl)phthalan, having methyl and phenyl radicalson each nitrogen atom, which gives a somewhat yellowish green coloredform.

The S-amino derivative of 1,1-bis(p-aminophenyl) phthalan having thestructural formula 2N- NHi 7 a 4] W IiIHr may be brought into contactwith an active phenolic developer material to produce a violet-red orbluish-red dark colored form of fair intensity. A deeper, bluishvioletcolored substance may be produced from 5-arnino-1,1-bis(p-methylaminophenyl)phthalan.

Among the more preferred S-amino derivatives of 1,1-bis(p-aminophenyl)phthalan, however, may be mentioned 5 dimethylamino1,1 bis(p dimethylaminophenyl) phthalan, forming a bluish violetquinonoid substance. Another N-substituted modification of the S-aminoderivative is, for example, S-anilino-l,1-bis(p-anilinophenyl) phthalan,which has three N-monophenyl-substituted amino groups and gives greenishblue to blue dark-colored quinonoid materials.

It will appear that N-substituted 1,1-bis (p-aminophenyl) phthalan and6-amino-1,1-bis(p-aminophenyl)phthalan compounds are particularlydesirable for use in systems in which white or light-coloredchromogenous compounds are converted to dark-colored forms. Thus, forsuch use there may be provided advantageously a colorless or lightlycolored chromogenous compound having a modified 1,1-diphenylphthalanstructural formula 0 C lHz which includes the three points, designatedthereon the p,p',5-positions, each para to the position of a bond to themethane carbon atom occupying the 1-position, and which is modified bythe inclusion of an amino radical in at least the first-mentioned two ofthe three p,p',5-positicns. Each such amino radical furthermore has atleast one substituent selected individually from the group consisting ofan alkyl radical or not more than four carbon atoms, the benzyl radical,and the phenyl radical. When the firstrnentioned two p,p'-positionscarry such amino radicals, the compound is a 1,1-bis(p-an1inophenyl)phthalan with one or two substituents for the hydrogen atoms in eachamino radical. When all three p,p',5-positions carry such aminoradicals, the compound is, of course, an N-substituted 5-amino-1,1-bis(p-aminophenyl)phthalan.

Turning now to the 2,2-epoxy derivative of 1,1-bis(p-aminophenyDphthalan, this derivative without further substituents is3',6-diaminospiro(phthalan-1,9-xanthene) having the structural formulaThis compound develops a generally red or bluish red color upon contactwith various phenolic developers. However, a colorless or lightlycolored chromogenous compound is preferred in the form of a substituted3',6'- diaminospiro (phthalan-1,9'-xanthene) compound, having thestructural formula shown just above, in which each of the amino radicalsalso has at least one substituent selected individually from the groupconsisting of an alkyl radical of not more than four carbon atoms, thebenzyl radical, and the phenyl radical. Accordingly, a more intensebluish red is obtained from the corresponding N-monoalkyl-substitutedchromogenous compound 3,6- bis(ethylamino)spiro(phthalan-1,9'-xanthene),while a still more intensely colored quinonoid form having a red orsomewhat bluish red color may be obtained from the N-dialkyl-substitutedcompound 3',6'-bis(dimethylamino)spiro(phthalan 1,9 xanthene). Theamino- 2,2" epoxy derivatives of 1,1 bis(p aminophenyl) phthalan may beexemplified by the N-substituted compound 3',5,6tris(dimethylamino)spiro(phthalan 1,9- xanthene), which develops a veryintense reddish violet color.

The compounds given in the above examples, having the S-memberedheterocyclic ring containing the hetero oxygen atom, may be referred toas cyclic ethers. Compounds of this type, and webs carrying transfercoatings containing such compounds, are disclosed and claimed in theconcurrently filed application for Letters Patent of the United StatesSerial No. 135,307, entitled Chromogenous Amino Derivatives ofDiphenylphthalan and Marking Method Using Same, filed in the names ofJohn R. Johnson and Earl J. Gosnell and assigned to the same assignee asthe present invention.

Such cyclic ether compounds without the epoxy. bridge may be prepared byreduction of the corresponding lactones of p-arnino-substitutedtriphenylmethanes, namely 3,3-bis(p-aminophenyl)phthalide,6-amino-3,3-bis(p-aminophenyl)phthalide, and the N-substitutedderivatives thereof. Procedures for making these lactones are discussedin U.S. Patents Nos. 2,417,897, 2,474,084, and 2,597,965 to Adams andNo. 2,742,283 to Crounse.

The synthesis of the cyclic ethers from such lactones may be achievedwith the use of anhydrous aluminum lithium hydride; for example, aboutgrams of the AlLiH may be refluxed with about 0.025 mole of theappropriate lactone in 350 ml. of ethyl ether for several hours. Afteradding water, the ether layer is decanted and dehydrated, and the etheris evaporated to obtain the solid product, usually having a white orlight pastel color. If the solid chromogenous material which has beensynthesized is darker than a medium pastel shade, repeated purificationtreatments using standard procedures, such as solvent or freezecrystallizations and selective solvent extractions, as with ether, canbe expected to yield a light-colored product approaching a colorless,that is, white, solid. Such chromogenous substances can be incorporatedreadily on paper in transfer coatings which appear substantially whiteor which have a creamy color quite acceptable as an ordinary papersurface.

Synthesis of the cyclic ether compounds with the epoxy bridge, namelythe 2',2"-epoxy and 5-amino-2,2"-epoxy derivatives of1,l-bis(p-aminophenyl)phthalan with N- substituents as desired, also mayuse a lactone as a starting material. Lactones with the epoxy bridge maybe formed by reaction, in the presence of ZnCl of phthalic anhydride or4-aminophthalic anhydride and m-aminophenol, with appropriatesubstituents for the amino hydrogen atoms in both of these reagents. Theaminophenol conveniently may be melted and the other materials dispersedin the melt. The mixture is maintained in molten condition during thereaction period, at the conclusion of epoxy bridge.

which the melt contains in major amount 3',6-diaminofiuoran having thestructural formula with corresponding substituents. Thus, if4-aminophthalic anhydride is used, the lactone compound has a S-aminogroup. Similarly, the aforementioned substituents for the hydrogen atomsin the amino groups of both reagents appear as N-substituents in thisfiuoran product, known in the art as a rhodamine lactone or colorlessbase. The lactone conveniently may be separated from the crude reactionmixture by digestion in dilute aqueous ammonium hydroxide to dissolveother materials and convert the lactone to solid particles of thecorresponding carbinol or color base, which are filtered off, washed,and dried. Refluxing the carbinol in benzene under dehydratingconditions effects recovery of the colorless or lightly colored lactoneproduct shown above in the structural formula for diaminofluoran.

Alternatively the lactone product may be obtained from the commercialrhodamine dye, such as Rhodamine B. The dye, incidentally, may beobtained conventionally by extracting the carbinol or color base,produced as above, with benzene and further extracting the resultingbenzene solution with dilute hydrochloric acid, whereupon crystals ofthe purified dye separate from the aqueous acid solution on cooling.When starting with the dye, the carbinol is regenerated by treatment ofan aqueous solution of the dye with sodium hydroxide, extracting,filtering, and drying, followed by the above-mentioned refluxing inbenzene under dehydrating conditions to close the lactone ring and formthe fiuoran product.

Refluxing the substituted 3,6-diaminofluoran, or rhodamine lactone,material thus obtained in anhydrous ether containing aluminum lithiumhydride effects reduction to the desired corresponding cyclic ethercompound with the This substituted 3,6' diaminospiro-(phthalan-l,9'-xanthene) compound may be termed a rhodamine cyclicether. Such a reduction procedure is analogous to the reduction of the3,3-bis(p-aminophenyl) phthalides to their corresponding cyclic ethersutilizing aluminum lithium hydride, as described above. While therhodamine lactones themselves are chromogenous compounds useful in theproduction of colored forms in accordance with the present invention, aswill be mentioned hereinbelow, the corresponding rhodamine cyclic ethersexhibit considerably greater stability against premature conversion tocolored forms and are considered preferable for use in accordance withthe present invention.

Turning next to the 3-oxo derivative of 1,l-bis(p-aminophenyl)phthalan,this compound is a lactone having the structural formula Ens-O ONE: J 1i1 co I.

N-substituents as desired, this is the same phthalide substance alreadymentioned in connection with the synthesis of the cyclic ethers. Theunsubstituted 3,3-bis(paminophenyl)phthalide develops a violet colorupon intimate contact with a recommended phenolic color-activatingsubstance. A more intense, greenish blue color can be obtained using3,3-bis(p-methylaminophenyl)phthalide. However, formation of darkerquinonoid compounds can be expected from N-tetraalkyl-substitutedcompounds. Thus a considerably more intense green or somewhat bluishgreen color is developed using 3,3bis(p-dimethylaminophenyl)phthalide,which conveniently may be referred to as the lactone of leuco-malachitegreen, and an excellent dark, intense, bluish green quinonoid form alsois produced from 3,3-bis(p-diethylaminophenyl)phthalide. Similarly, ablue-green color is obtained with 3,3-bis(p-dipropylaminophenyl)phthalide. Also quite satisfactory, althoughnot N-alkyl-substituted, is 3,3-bis(p-dibenzylaminophenyl)phthalide,giving a greenish blue colored form.

The -amino-3-oxo derivative of 1,1-bis(p-aminophenyl)phthalan, also alactone, is better named 6-amino-3,3- bis(p-aminophenyDphthahde, havingthe structural formula Preparation of this triamino-substituted3,3-diphenylphthalide also is mentioned above. A violet-red or bluishred color may be developed from this compound, as shown without aminosubstituents. Bluish-violet colors generally are obtained in thequinonoid forms of such compounds which have two or preferably threeN-alkyl substituents, such as 6-amino3,3-bis(p-methylarninophenyl)phthalide and 6 ethylamino 3,3 bis(pethylaminophenyl)phthalide. However, for the property of rapidproduction of intense, dark, bluish violet quinonoid forms it ispreferred to use N-hexaalkyl-substituted compounds. These areexemplified by 6-dimethylamino-3,3- bis(p-dimethylaminophenyl)phthalide,also identified as crystal violet lactone, and by6-diethylamino-3,3-bis(pdiethylaminophenyl)phthalide and the samecompound with three dipropylamino groups in place of the diethylaminogroups. Considered particularly desirable for the production of bluishviolet colored forms is 3,3-bis(pdiethylaminophenyl)-6-dimethylarninophthalide, for which there may be substituted thecompound 3,3 bis(pdiisopropylaminophenyl) 6 dimethylaminophthalide.Similar properties also are obtained with n-butyl groups, as in6-dibutylamino 3,3 bis(p dibutylaminophenyl) phthalide. Again, benzyland phenyl substituents may be used in place of alkyl substituents.Thus, a different color for the quinonoid form may be obtained from 6-N-benzyl N methylamino 3,3 bis (p N benzyl N-methylaminophenyl)phthalide having a red-violet quinonoid form, and thecompound 3,3-bis(p-anilinophenyl)- 6-dimethylaminophthalide has a bluedark-colored form.

It will appear from the foregoing that the N-substituted3,3-bi-s)p-aminophenyDphthalide and 6-amino-3,3-bis(paminophenyl)phthalide compounds are preferred for their goodchromogenous properties. Such colorless or lightly colored compounds maybe defined as chromogenous colored reddish violet substance.

compounds having a modified 3,3-diphenylphthalide structural formula atb which includes the three points, designated on the above formula asthe p,p',6-positions, each para to the position of a bond to the methanecarbon atom occupying the 3- position in this formula, and which ismodified by the inclusion of an amino substituent in each of at leastthe first-mentioned two of the three p,p',6-positions. When those twop,p'-positions have that substituent, the compound is a3,3-bis(p-aminophenyl)phthalide, and when all three p,p',6-positionshave that substituent, the chromogenous compound is in the form of a6-amino-3,3- bis(p-aminophenyl)phthalide. Again, each of the aminoradicals in these compounds should have at least one subtituent selectedindividually from the group consisting of an alkyl radical of not morethan four carbon atoms, the benzyl radical, and the phenyl radical.

The examples mentioned above indicate that the alkyl groups in thesecompounds advantageously are methyl, ethyl, n-propyl, and isopropylgroups. A particular preference is noted for thehexaalkyl-triamino-substituted 3,3- diphenylphthalide chr-omogenouscompounds, in the form of 6-dialkylamino-3,3-bis (pdialkylaminophenyl)phthalide compounds in which each individual alkylradical of the three dialkylamino groups has not more than three carbonatoms.

The 2',2"-epoxy 3 oxo derivative of 1,1 bis(paminophenyl)phthalan is3',6'-diaminofluoran having the structural formula HEN which can be usedto develop a reddish color with a tinge of blue or violet. TheN-substituted derivatives or rhodamine lactones are preferred, and theirsynthesis by known procedures is summarized hereinabove. Better colorintensity of the quinonoid form is obtained from3,6'-bis(ethylamino)iiuoran and still deeper color from 3 diethylamino 6ethylaminofluoran, which is the lactone of RllOd-Ettll'llllfi 4G, whilea preferred chromogenous amino-substituted fiuoran is3',6-bis(diethylamino)fluoran, the lactone of Rhodamine B; thesechrornogenous compounds have bluish red quinonoid darkcolored forms. Thecompound 3','6'-dianilinofluoran also is useful and forms a violetdark-colored substance. Compounds which may be viewed as5-amino-2',2"-epoXy-3- oxo derivatives of1,l-bis(p-aminophenyl)phthalan, in other words 3,5,6'trian1inofluroan,with N-substituents, also may be obtained, as by the synthesis mentionedabove using the reagents 4-aminophthalic anhydride and maminophenol withcorresponding N-substitu-ents; an example is the chromogenous compound3',5,6'-tris(dimethylamino)fluoran, which can form a very intensely Thelactone ring structure present in these aminofluoran compounds has atendency to open with consequent premature formation of a coloredmaterial, and it has been reported that this tendency is fostered in thepresence of highly polar solvents such as alcohol, acetone, and water.Accordingly, when these chromogenous compounds are used, they should beprotected against contact with such materials or vapors prior toformation of the desired permanent dark colored forms by contact withthe color-activating material on the face-coated sheet in accordancewith the invention; or corresponding rhodamine cyclic ethers may beused.

Coming now to the bifunctional derivatives of 1,1-bis(paminophenyDphthalan having a second heterocyclic ring fused to the 5,6side of the benzene nucleus, these derivatives will be seen to be basedon the compounds having the structural formula lTIHr I NH: and theisomeric structural formula ITIH: IIIHQ These isomeric compounds may benamed respectively 1,1,5,5-tetrakis(p aminophenyl) 7 hydro 1H,3H-

benzo(1,2-c:4,5-c')difuran and 1,1,7,7-tetrakis(p-aminophenyl) 5 hydro-1H,3H-benzo(1,2 c:4,5-c')difuran.

Each of these two compounds has two heterocyclic furan rings fused tothe central benzene nucleus, and each of these furan rings includes onecarbon atom carrying two unsubstituted hydrogen atoms, as may be seen atthe bottom of the last structural formula shown above.

The last mentioned carbon atoms may be oxo-substituted; that is, the twohydrogen atoms carried by each carbon atom may be replaced by an oxygenatom. Each furan ring thus assumes a gamma-lactone structure, instead ofthe cyclic ether structure, giving a bifunctional lactone, or dilactone,compound. The respective dilactone compounds may be named3,3,7,7-tetrakis(p-aminophenyl) 1H,3H benzo(l,2-c:4,5-c')difuranl,5(7H)- dione and 3,3,5,5-tetral is(p-aminophenyl)-1H,3H-benzo-(1,2-c:4,5-c)-difuran-1,7(5H) -dione.

Dilactone compounds of the last mentioned type are disclosed and claimedin the concurrently filed applicationed for Letters Patent of the UnitedStates Serial No. 135,264, entitled chromogenous Aminophenyl Derivativesof Benzodifurandione and Marking Method Using Same, filed in the namesof Earl J. Gosnell and John F. McCarthy, Jr., and assigned to the sameassignee as the present invention. A representative N-substituteddilactone compound may be synthesized by dissolving one mole ofN,N-dimethylaniliue in about four times its weight of carbon disulfideand stirring in about 0.9 mole of anhydrous aluminum chloride as acatalyst. After dissolution of the AlCl 0.2 mole of pyromelliticdianhydride is added, stirred, and allowed to stand. The upper layer ofCS is decanted and 1250 ml. of 8% sulfuric acid added to it slowly.After dilution with about 10 liters of water and standing, the firststage of the synthesis gives an approximately yield of a solidintermediate product which is a mixture of two isomeric compounds havingthe structural formulas o o o o 0 CX XG C-X and on no on where eachradical designated X is the p-dimethylaminophenyl radical derived fromthe N,N-dimethylaniline. In the second stage of the synthesis, a portionof the isomeric intermediate mixture then is heated at reflux temmraturefor 24 hours, with a further amount of N,N-dimethylaniline equal toabout 4.5 to 5 times the equimolar weight, in a volume of liquid aceticanhydride weighing about 7 to 8 times as much as the weight of theN-substituted aniline. Cooling and filtering gives a solid aceticanhydride-insoluble product of light yellow color, and pouring thefiltrate over crushed ice and filtering gives a solid aceticanhydride-soluble product of light greenish yellow color, both in goodyields. A mixture of these two solid products may be obtained byflushing with ice water before filtering out the aceticanhydrideinsoluble fraction.

These two light colored products are the chromogenous substancesselected from the group consisting of the isomeric compounds having thestructural formulas where X is as above and the radical designated Xalso is the p-dimethylaminophenyl radical, derived in this instance fromthe dimethylaniline used in the reaction with the intermediate mixture.It will be appreciated that aniline itself, or other N-substitutedanilines, may be used in forming the intermediate mixture withcorresponding variations in the p-arninophenyl radical X, while aniline,or still another N-substituted aniline, may be used as the reagent withthe intermediate isomers to get the dilactone product with othercorresponding variations in the p-aminophenyl radical X. Yields of theacetic anhydride-insoluble and -soluble fractions vary, and standardpurification procedures such as solvent or freeze crystallizations andselective solvent extractions can be utilized where necessary to recovercrystalline products having substantially colorless creamy or lightpastel shades. The dilactones generally can be heated well above 300 C.without melting or decompisition.

The synthesis of a specific chromogenous dilactone compound, or isomericmixture of such compounds, having the structure represented by theformulas given above where all of the radicals designated both X and Xare p-dimethylaminophenyl groups, is mentioned hereinabove by way ofexample. The two isomeric fractions have very low solubilities in mostof the common organic solvents. However, they dissolve up to a fewpercent or more in some of the solvent vehicles such as the simple orchlorinated phenyl ethers and chlorinated polyphenyls, and the solutionof either one or both of the above-mentioned fractions givesinstantaneously a dark blue-green colored form when brought into contactwith one of the phenolic substances listed hereinabove.

Indicating the variety of dilactone chromogenous compounds which can beutilized in accordance with the present invention, the use ofunsubstituted aniline in the synthesis described above gives thetetrakis(p-aminophenyl)benzodifurandione or dilactone substance withoutN-substituents, X and X both being p-aminophenyl radicals, and contactwith developers yields a reddish or purplish tan colored form. It ismuch preferred, however, to use substituted anilines, particularlyN,N-disubstituted anilines. Thus the N,N-dimethylaniline advantageouslyis used in many cases to make the intermediate product having thep-dimethylaminophenyl group for the radical X. However, appropriatevariations in the substituted aniline reacted with the intermediateproduct in the second stage of the synthesis described above yielddilactone products in which the radical X consists of differentN-substituted p-aminophenyl groups, preferably otherN-dialkyl-substituted groups with alkyl radicals of not over threecarbon atoms. X accordingly may be the p-diisopropylaminophenyl radical,while X remains the p-dimethylaminophenyl radical. This dilactonesubstance also gives a dark blue-green quinonoid form on contact with aphenolic developer material. Blue-green forms also are obtained from thedilactone in which X is the p- I-benZyl-N-ethylaminophenyl group, whilethe dilactone in which X is the p-dibenzylaminophenyl group gives abluish green to green dark colored forms. Corresponding and sometimessuperior results can be obtained with halo or methyl substituents on thephenyl ring in the p-aminophenyl radical. Thus, when Ill-ChlOI'O-N,N-diethylaniline is used in the second stage of the synthesis, theresulting dilactone product has o-chlorop-diethylaminophenyl groups forthe X radicals, X still remaining the p-dimethylaminophenyl group. Thissubstance gives a green dark colored form. When X is thep-diethylamino-o-tolyl group, the quinonoid form has a strong dark greencolor. Thus certain compounds, with halo and methyl substituents in theortho, and meta, positions of the p-aminophenyl groups, are equivalentto the compounds without such substituents.

A preferred dilactone substance of the type just described, havingdialkylaminophenyl groups, will be seen to include a colorless orlightly colored chromogenous compound based on the structure ofpyromellitic dianhydride including, fused to opposite sides of thebenzenes nucleus, two heterocy-clic rings each containing a heterooxygen atom in the ring, and to each of which two other oxygen atoms areattached. One of these two oxygen atoms attached to each heterocyclicring thereof is replaced by two p-dialkylaminophenyl groups, in whicheach individual one of the four alkyl radicals has not more than threecarbon atoms.

Instead of a dilactone substance, there may be used the correspondingbifunctional cyclic ethers, which are the usually N-substitutedderivatives of the 1,1,5,5-tetra kis(p aminophenyl) 7 hydro 1H,3Hbenzo(1,2 c:4,5-c)difuran and of its isomer, shown above. To produce thebifunctional cyclic others, or dicyclic ethers, appropriate dilactones,such as those just mentioned, may be added to ethyl ether Which ismaintained at reflux temperature and which contains aluminum lithiumhydride, and the bifunctional cyclic ether recovered by filtration andsolvent exaporation. These products after purification have chromogenouscharacteristics similar to those of the corresponding dilactonematerials, hav-,

ing the same N-substituted p-aminophenyl groups represented by theradicals X and X in the structural formulas shown above.

In addition to such bifunctional cyclic ethers, and the bifunctionallactones, or dilactones, already described, the correspondingbifunctional derivatives of 1,l-bis(p aminophenyl)phthalan having theepoxy bridges also may be used. In this category the diepoxy-substituteddilactones have the isomeric structural formulas and the amino hydrogenatoms again preferably are replaced by alkyl, benzyl, or phenylradicals. Thus all of the amino groups may be dialkylamino groups inwhich each alkyl radical has no more than three carbon atoms, e.g.,dimethylamino groups or diethylamino groups.

As an example, the isomeric substance having diethylamino groups may beobtained by heating one mole of m-diethyl-aminophenol and roughly onemole of anhydrous zinc chloride with 0.2 mole of pyromelliticdianhydride o o C /C\ 0 O o o 0 0 for several hours at C. while stirringthe melt, to form in the melt a moderate yield of a bifunctionalcompound including the structure It will be seen that the portion of themolecular structure illustrated here is the lactone of Rhodamine B, thatis 3',6-bis(diethylarnino)fluoran. It will be understood further thatthe pyromellitic dianhydride acquires a similar spire-linked xanthenestructure, not illustrated here, on the other side of the benzenenucleus, where another one of the dianhydride carbonyl oxygen atoms isreplaced with two more aminophenyl radicals. Thus a third molecule ofwater is split off, formed from this oxygen atom and the hydrogen atomsin the 6-positions on two additional 3-diethylaminophenol molecules. A

second xanthene epoxy bridge also is formed by removal of a fourth watermolecule from the two adjacent phenolicrhydroxyl groups in these twoadditional aminophenol molecules.

To recover this product from the reaction mixture, a procedure relatedto that indicated hereinabove in connection with production of thefamiliar rhodamine lactones then may be followed. Thus the melt,containing the reaction product formed from the pyromellitic dianhydrideand the B-diethylaminophenol, may be cooled, finely powdered, anddigested with dilut eaqueous ammonium hydroxide, leaving undissolved thebifunctional carbinol JKONUJZ QI C-OH O This substance is separated byfiltering it out of the ammonium hydroxide solution, washing with freshdilute ammonium hydroxide, and drying. Reclosure of the two lactonerings is accomplished by refluxing the carbinol with benzene, whichconveniently is done with a standard condenser and Stark and Dean tubeapparatus to remove the water split off from the carbinol hydroxylgroups and the adajcent carboxyl hydrogen atoms. The resulting benzenesolution is then filtered and evaporated under vacuum to recover thebifunctional rhodamine lactone substance, whose structure is illustratedby the isomeric formulas shown above, all the amino hydrogen atoms beingreplaced by ethyl radicals in this example.

This product is more or less colorless, having a creamy to light pinkcolor. By using other N-substituted mor S-aminophenols, a variety ofother. chromogenous rhodamine dilactone compounds, having differentN-substituents and also only lightly colored, may be prepared, as willbe understood from a consideration of the various N-substituteddilactont compounds discussed hereinabove, which are the correspondingbifunctional lactones without the epoxy bridges. The colored forms ofthese rhodamine dilactone substances resemble in hue the colored formsof the corresponding rhodamine lactones, giving generally bluish redcolors. However, the rhodamine dilactone substances share with themonofunctional rhodamine lactone compounds a tendency toward prematureopening of the lactone rings, which may cause coloration of thechromogenous material before marking contact has been effected with thedesired coloractivating material. Of course, the rhodamine dilactonesubstance may be protected from premature contact with atmospheric orother environments which permit pre' mature coloring.

However, it may be preferable to convert the rhodamine dilactones to thecorresponding bifunctional cyclic ether substances, which haveconsiderably more stability against adventitious color formation as whenexposed to a humid atmosphere. Such bifunctional cyclic ether substancesinclude the structure with suitable N-substituents. Each monofunctionalmolecular arrangement in this category of bifunctional substances willbe seen to include the structure of3',6'-dia-minospiro(phthalanl,9'-xanthene), as illustrated. here. Thesebifunctional cyclic ether substances likewise may have either, or amixture of both, of the isomeric forms corresponding to the two isomericstructural formulas given above for the rhodamine dilactone substances.Any two isomeric compounds of this structure give very similar coloredforms, which also are similar in hue to the colored forms produced fromthe corresponding rhodamine dilactone and rhodamine lactone substances,although with some N-substituents minor differences in hue may beobserved, even between isomeric pairs, depending on the color-activatingsubstance used.

All of the bifunctional substances in the categories of bifunctionallactones, cyclic ethers, rhodamine lactones, and rhodamine cyclic ethershave high melting points and generally can be heated above 300 C. in aneutral atmosphere without melting or decomposing. Several nonpolar ormildly polar solvents may have tobe tried in order to find one whichwill dissolve several percent or more of these bifunctional chromogenoussubstances.

The bifunctional rhodamine cyclic ethers, having the functionalarrangement illustrated above, are obtained by reduction of thecorresponding chromogenous rhodamine dilactone substances, using eitherof the isomeric forms thereof or a mixture of such forms. The rhodaminedilactone is stirred slowly into a semidissolved mixture of aluminumlithium hydride in anhydrous ethyl ether. The resulting mixture isrefluxed to permit reaction, cooled, and water is added dropwise. Theether layer is decanted, dried with a solid desiccant such as anhydroussodium sulfate, and the ether evaporated to obtain the chromogenous,substantially colorless or light pink, solid rhodamine dicyclic ethersubstance.

The chromogenous bifunctional compounds comprising the dicyclic ethersreduced from dilactone substances, the rhodamine dilactone substanceswith the epoxy bridges, and the bifunctional rhodamine dicyclic ethersprepared therefrom as just described, are disclosed and claimed in aconcurrently filed application for Letters Patent of the United StatesSerial No. 135,359, entitled Chromogenous Tetrakis(aminophenyl)Derivatives of Benzodifuran and Marking Method Using Same, filed in thename of Earl J. Gosnell and assigned to the assignee of the presentinvention.

All of the monofunctional and bifunctional chromogenous compoundsdescribed hereinabove have a bis(paminophenyl) methyl group, or a3,6-diamino-9-xanthenyl group, with an additional linkage from themethyl carbon atom in the former, or from the carbon atom designated 9in the latter, to the hetero oxygen atom. Some of the monofunctionalcompounds have a third amino radical, on the benzene nucleus one side ofwhich is in the heterocyclic ring. In the preferred chromogenouscompounds these amino radicals have substituents, for which the methyland ethyl N-substituents are chosen frequently. Propyl and butylsubstituents for one or both of the amino hydrogen atoms provide quitesimilar properties, so that alkyl radicals of not more than four carbonatoms are suitable. Examples of N-benzyl and N-phenyl groups also appearhereinabove.

Equivalent results also may be obtained, for example, with certainsaturated monoalkyl radicals having five carbon atoms or with themono-n-hexyl radical as N-substituents, and N-substituted cycloalkylgroups such as the cyclopropyl and cyclohexyl groups may be present, butthese N-substituents are not preferred. As further examples, theN-phenyl-substituted compounds may be modified by including naphthylradicals instead of phenyl radicals as N-substituents, or certain smalladditional substituents may be included on the N-substituted radicalsmentioned above, and generally equivalent properties still will beobtained; in this connection such N-substituted groups as thechloromethyl, hydroxyalkyl (e.g., betahydroxyethyl, gamma-hydroxypropyl,or delta-hydroxybutyl), sulfophenyl, tolyl, or one of the methylbenzylradicals may be mentioned. Equivalent to the aminophenyl groupsthemselves in some chromogenous compounds are amino-l-naphthyl groups;thus 4-diethylamino-l-naphthyl groups may replace p-diethylaminophenylgroups. Instead of N-substituted amino groups, equivalent results alsomay be expected with piperidino groups, or an entire N-substitutedp-aminophenyl group may be replaced by the 9-julolidyl radical It willbe appreciated likewise that substantially equivalent properties alsoare obtainable in the chromogenous compounds when one small substituentor several small substituents, notably one or more methyl, chloro,bromo, fluoro, or nitro radicals, is or are substituted for one or moreof the available hydrogen atoms on the phenyl rings in the aminophenylradicals or on the benzene nucleus one side of which is in theheterocyclic ring.

It should be noted that the choice of one of the phenolic materialsdisclosed herein as the color-activating material to be used with aparticular chromogenous substance, or the choice of the chromogenoussubstance to be used together with a particular phenolic material, mayrequire the exercise of the good judgment of one experienced in the art,and in some instances a little experimentation, to arrive at anefiective or reasonably satisfactory combination of materials for aspecific system. Certain combinations of such phenolic substances andchromogenous substances naturally give the best results in terms ofrapid development of very dark and intense colored forms upon ordinarycontact of the two substances. The same chromogenous substance canproduce dark-colored forms having noticeably different color responsesor hues when brought into contact with different ones of the phenolicmaterials useful as color-activating substances, and the color intensityof the colored forms produced in a given system or arrangement can showgross variations when different phenolic materials are used. The colorsgiven hereinabove for the dark-colored or quinonoid forms of certainchromogenous substances are examples of the colors ordinarily obtainedwhen quite active color-developing phenolic compounds are used. Whilethe phenolic materials useful in accordance with the present inventionproduce dark-colored forms of useful intensities after being broughtinto ordinary contact with many chromogenous materials, the use of someof the phenolic substances identified hereinabove which exhibit somewhatlower reactivity as color developers than the best of thesecolor-activating substances, or the use of a less reactive chromogenouscompound, may require the application of heat, or utilization of othermeans of obtaining more intimate contact of the materials, to causereasonably good color development. This might be accomplished, forexample, by concentrated infrared irradiation or by conductive contactwith a hot surface. For each combination of chromogenous andcolor-activating materials which is to be used, it has been found highlydesirable to try a number of solvent liquids for the chromogenouscompound, or for the color developer when it is to be dissolved, toobtain the concentration and other environmental conditions which favorthe efiicient formation of a dark-colored material with desirable colorintensity and hue.

As already discussed, the chemical structure of the dark colored formsproduced from these chromogenous compounds by the action of the phonolicsubstances has not been established, and accurate analytical methods forproviding dependable and incontrovertible evidence of their chemicalstructure apparently are not available. It is presumed, however, thatthe phenol or some substantial residue thereof remains bonded orassociated with the colored form to which the chromogenous compound isconverted, since the colored materials differ, in improved resistance tomoisture and in other characteristics, from the colored materialsproduced with inorganic colordeveloping materials and with the acidsproposed for that purpose. Accordingly there is provided a newcomposition of matter, comprising the dark colored substance obtained byintimate contact of the selected phenolic substance with one of thecolorless or lightly colored chromogenous compounds. These newcompositions formed by the action of the phenolic substances on thechromogenous compounds may be classified as novel dyestuffs which inmost cases are spirit-soluble and oil-soluble.

When these dark colored materials are formed, the method is beingcarried out, embodying an aspect of the present invention, in whichdark-colored materials are developed from chromogenous compounds bybringing a colorless or lightly colored chromogenous compound, whichincludes as its major functional arrangement the molecular structureinto reaction contact with a substance selected from the group ofphenolic substances listed above. It will appear from the above thatmarking or printing may be accom plished, without the use ofconventional inks containing dark pigments or colored dyes, by usinginstead of such inks an oily ink vehicle in which the chromogenouscompound is dissolved. For letterpress printing, by way of example, theresulting, substantially colorless oily vehicle is applied to the type,which then is impressed on a web surface having a coating containing thephenolic substance to develop dark characters on the web. Alternatively,sheets having such a face coating may be used in a typewriter, which issupplied with a ribbon impregnated with an oily ribbon-inking vehiclecontaining one of the chromogenous substances in solution. Neither theribbon so impregnated nor the face-coated sheets will soil the fingersor clothing.

Such arrangements illustrate the method of the invention involving, morespecifically, the marking on a substrate by developing dark coloredmaterials from chromogenous compounds, in which one of the chromogenouscompounds specified above is provided, preferably dissolved in an oilyvehicle, and is brought into contact, in areas on the substrate wheremarking is desired, with the phenolic compound to produce marks in suchareas of the dark colored product formed from the two compounds. In theillustrations just given, the phenolic colordeveloping material had beenapplied to the web, sheet, or other substrate, prior to bringing thechromogenous material into contact with the surface of the web, so thatthe web carries the phenolic material evenly distributed in amountspreferably of from 0.2 to 8 grams per 1,000 square inches or" websurface. It will be understood that the chromogenous material may bebrought into contact with the phenolic developer in many other ways,some being suggested hereinabove, whether or not the chromogenousmaterial itself actually is transported to efiect the contact. Thephenolic compound may be carried t0 the chromogenous compound, or bothcompounds may be brought into a new location to effect mutual contactthere.

To give another illustration, the chromogenous material may be cementedin solid form on a paper web, using for example a starch binder, and thenecessary contact then may be effected through the application of smallquantities of the phenolic compound, dissolved in a solvent or at atemperature at which the phenolic compound in either pure or impurecondition is in the liquid state, to the surface coating in the form ofliquid droplets applied where dark colored marks are desired. Both thephenolic compound in such liquid form and the chromogenous compounddissolved in a solvent alternatively may be applied sequentially to asurface to form marks thereon, or the two liquids may be contained inindividual rupturable capsules on the same surface. Of course, themarking method may be carried out by the use of the manifolded. setsdescribed hereinabove. Any of the l,l-bis(p-aminophenyDphthalanderivatives may be used as the chromogenous compound, the 0x0substituted 3,3 bis(p aminophenyl)phthalides and6-amino-3,3-bis(p-aminophenyl)phthalides having N- substituents oftenbeing preferred; although an N-substituted1,l-bis(p-aminophenyl)phthalan or 5-amino-l,lbis(p-aminophenyl)phthalan,or an N-substituted 3',6- diaminospiro(phthalan-l,9-xanthene), or one ofthe dilactone substances with p-dialkylaminophenyl groups, also usuallyis particularly suitable for the purpose. Some of the most active of thephenolic substances, preferred for use in the marking method of theinvention, and for forming the novel dark colored compositions of theinvention by that or other methods, have been pointed out moreparticularly hereinabove.

Use of the phenolic color-developing substances provided in accordancewith the present invention in modified spirit-duplicating systems isattractive. Two colorless or lightly colored substances are provided insuch duplicating methods embodying the invention, one of these twosubstances being a chromogenous compound as specified herein, and theother of the two substances being one of the phenolic substances.Deposits are formed, on the surface of a master sheet, of a preselectedone of these two substances in areas representing an image to beduplicated but with mirror-reversed image elements. These depositsshould contain the preselected chromogenous or phenolic material in abinder which is insolublein the duplicating fluid or spirit to be used,the fluid thus being a solvent for the aforesaid preselected materialwhich is to be transferred but not for its binder.

There is more than one way to use the spirit transfer principle toobtain many duplicate copies from this master sheet. In one variation ofthis duplicating method, a solution of the remaining one of the twosubstances in a solvent liquid is applied to the surface of eachduplicate sheet in sequence. The duplicate sheet surface, wetted withthe solvent liquid containing the remaining one of the two substances,is pressed against the master sheet surface to effect transfer by thesolvent liquid of portions of the deposits of the preselected one of thetwo substances from the master sheet surface to the duplicate sheetsurface onto the areas of the latter which represent the image. By thisprocedure a duplicate image is formed, on the duplicate sheet surface,of dark colored material produced by the action of the phenolicsubstance on the chromogenous compound.

This method may be carried out by forming a reversed image of depositsof the phenolic substance on the master sheet, and then Wetting theduplicate sheets with a solvent liquid containing the chromogenouscompound. However, it is preferred to use the chromogenous material formaking the image-representing deposits on the master sheet. The reverseimage conveniently can be formed using transfer sheets or ribbonscarrying the chromogenous compound. Transfer ribbons accordingly may beimpregnated with the chromogenous material dispersed in a parafiin oil;or transfer coatings consisting of the chromogenous material, dispersedin a binder of wax or of a paraflin oil maybe formed on a web surface toprovide transfer sheets. Such a transfer sheet, for example, is placedin a type-writer beneath the master sheet with the transfer coatingfacing the master sheet. Typing or Writing with a stylus then causes areverse image to be formed of the chromogenous material transferred tothe lower master sheet surface, opposite the surface impressed with thetypes or the stylus. The successive duplicate sheets then are wettedwith a solvent liquid in which the phenolic developer substance isdissolved, whereby a duplicate image is formed, on the duplicate sheetsurface, of dark colored material produced by the action of the phenolicsubstance in the solvent liquid on the portions of the chromogenouscompound transferred by the solvent liquid from the master sheet surfaceto the duplicate shee-t surface. The solvent liquid may be, for example,acetone, toluene, benzene, Z-butanone (methyl ethyl ketone), or methylor ethyl alcohol. The solvent liquid and the binder used for thedeposits on the master sheet are chosen so that the binder is notdissolved during successive transfers of portions of the chromogenousmaterial from the master sheet to the duplicate sheets.

In another variation, a predetermined one of the two colorless orlightly colored substances again is used to form the depositsrepresenting the reversed image on the master sheet surface. Theprocedure is varied, however, by arranging the remaining one of the twosubstances to be carried on at lea-st one surface of the duplicatesheets, usually as a thin coating of the solid substance in a smallamount of an adhesive binder. Then a liquid, such as one of the volatileliquids just mentioned, which is a solvent for the preselected one ofthe two substances is applied to that surface of the duplicate sheet.The duplicate sheet surface, thus wetted with the solvent liquid, ispressed against the master sheet surface to cause portions of thepreselected one of the two substances deposited thereon to dissolve inthe liquid and to be transferred into contact with the remaining one ofthe two substances, carried on the duplicate sheet surface, in the areasrepresenting the image. By this procedure a duplicate image again isformed, on the duplicate sheet surface, of dark colored materialproduced by interaction of the two chromogenous and phenolic substances.

In the duplicating method just described, the preselected substance maybe the c-hromogenous compound, in which case the remaining substance,which is the phenolic substance, is carried on each duplicate sheet.Under certain circumstances, however, it may prove to be more feasibleto pick the phenolic compoundinstead as the preselected substance. Inpreparing the master sheet, the phenolic compound then is transferred ina binder to the master sheet surface in the configuration of thereversed image, and the chromogenous compound is carried on the activesurface of each duplicate sheet. Solvent spirits for the phenoliccompound are used, such as one of the solvents mentioned above whichdoes not readily affect the binder used in the phenolic deposits. Whenthe active surface of each duplicate sheet is wetted with this solventliquid and pressed against the master sheet surface, portions of theimage-representing deposits of the phenolic substance thereon dissolvein the liquid and are transferred into contact with the chromogenouscompound carried on the duplicate sheet surface, causing the darkcolored material to form in the areas on the duplicate sheet surfacerepresenting the image to be duplicated.

It appears from the discussion hereinabove that highly useful darkcolored marking materials or dyes are produced, when utilizing thearrangements and methods of the invention, by the action of the phenolicsubstances disclosed hereinab ove on suitable chromogenous compounds,the latter bcing exemplified by the bis(p-aminophenyl)phthalan cyclicether compounds, by the triphenylmethane lactones, and by the rhodaminelactone or colorless base compounds and by their cyclic ethers. Ascompared with the dark forms produced from the lactoncs by the action ofinorganic developer materials, or by the 37 action of weak acids such asacetic acid and tartaric acid, these new dark colors generally are morepermanent in nature, have increased resistance to fading underultraviolet radiation and to loss of color in the presence of moisture,and have improved color intensity.

While there have been described what at present are considered to be thepreferred embodiments of this invention, it will be obvious to thoseskilled in the art that various changes and modifications may be madetherein without departing from the invention. It is aimed, therefor, inthe appended claims to cover all such changes and modifications whichfall within the true spirit and scope of the invention.

What is claimed is:

1. A manifolding unit, comprising: a base 'we'b having on one side atransfer coating made up of a film-forming material which is rupturableupon impact and which contains as a timely dispersed phase numerouscells of a liquid vehicle, carrying dissolved therein a substitutedphenol having substituent radicals selected from the group consisting ofa single substituent which is one of the alkyl allyl, halo,halo-substituted alkyl, cycloalkyl, phenyl, halosubstituted phenyl,alkyl-substituted phenyl, biphenylyl, benzyl, and alpha-alkyl-benzylradicals, of any two sub stituent radicals and of any three substituentradicals included among said single substituents except when two of saidtwo or three substituent radicals are in the 2,6-positions relative tothe phenolic hydroxyl group, of the tetrarnethyl and tetrahalo radicals,of any of said substituent radicals and said groups of two, three, andfour substituent radicals with a second hydroxyl radical also on saidphenol, of the para-nitro radical, and of the pentamethyl and pentahaloradicals; said manifolding unit being adapted to produce a dark coloredmaterial, upon said impact and local rupture of said coating withrelease of said liquid vehicle into contact with a contiguous surfacecarrying a colorless or lightly colored chromogenous compound whichincludes as its major functional arrangement the molecular structure bythe action of said substituted phenol in said vehicle on saidchromogenous compound.

2. A manifolded set, comprising: a first base web having on one side atransfer coating made up of a filmforming material which is rupturableupon impact and which contains as a finely dispersed phase numerouscells of a solvent liquid vehicle; a second base web having on one sidean adherent coating, said first and second webs being maintaineddisposed together in face to face relationship with said respectivetransfer and adherent coatings in contiguity with each other; onecoating constituent in the form of a colorless or lightly coloredchromogenous compound which includes as its major functional arrangementthe molecular structure having a triphenylmethane group with a bond fromthe methane carbon atom thereof to the heterocyclic oxygen atom; andanother coating constituent in the form of a substituted phenol havingsubstituent radicals selected from the group consisting of a singlesubstituent which is one of the alkyl, allyl, halo, halo-substitutedalkyl, cycloalkyl, phenyl, halo-substituted phenyl, alkyl-substitutedphenyl, biphenylyl, benzyl, and alpha-alkylbenzyl radicals, of any twosubstituent radicals and of any three substituent radicals includedamong said single substituents except when two of said two or threesubstituent radicals are in the 2,6-positions relative to the phenolichydroxyl group, of the tetrarnethyl and tetrahalo radicals, of any ofsaid substituent radicals and said groups of two, three, and foursubstituent radicals with a second hydroxyl radical also on said phenol,of the para-nitro radical, and of the pentamethyl and pentahaloradicals; one of said coating constituents being dissolved in saidsolvent liquid vehicle present as said numerous cells in the transfercoating on said first base web, and the other of said coatingconstituents being bonded to said second web in said adherent coatingthereon but being accessible to other materials coming into contact withportions of the adherent coating; whereby, upon local impact and ruptureof said transfer coating, releasing said liquid vehicle containing saidone coating constituent from some of said cells onto said contiguousadherent coating, contact is effected between said two coatingconstituents to produce a dark-colored material by the action of saidsubstituted phenol in opening said bond from the methane carbon atom tothe heterocyclic oxygen atom to permit quinonoid resonance in saidchromogenous compound.

3. A manifolded set, comprising: a first base web having on one side atransfer coating containing a colorless or lightly colored chromogenouscompound which is transferable upon impact from said coating to "asurface contiguous therewith and which includes as its major functionalarrangement the molecular structure having a triphenylmethane group witha bond from the methane carbon atom thereof to the heterocyclic oxygenatom; and a second base web carrying on at least one active surface asubstituted phenol having substituent radicals selected from the groupconsisting of a single substituent which is one of the alkyl, allyl,halo, halo-substituted alkyl, cycloalkyl, phenyl, halo-substitutedphenyl, alkyl-substitu-ted phenyl, biphenylyl, benzyl, andalphaalkylbenzyl radicals, of any two substituent radicals and of anythree substituent radicals included among said single substituentsexcept when two of said two or three substituent radicals are in the2,6-positions relative to the phenolic hydroxyl group, of thetetramethyl and tetrahalo radicals, of any of said substituent radicalsand said groups of two, three, and four substituent radicals with asecond hydroxyl radical also on said phenol, of the para-nitro radical,and of the pentamethyl and pentahalo radicals; said first and secondwebs being maintained disposed together in face to face relationshipwith said transfer coating in contiguity with said active surface,whereby, upon said impact in localized areas, a dark-colored material isproduced locally by the action of said substituted phenol carried onsaid active surface in opening said bond from the methane carbon atom tothe heterocyclic oxygen atom to permit quinonoid resonance in saidchromogenous compound transferred to said active surface.

1. A MANIFOLDING UNIT, COMPRISING: A BASE WEB HAVING ON ONE SIDE ATRANSFER COATING MADE UP OF A FILM-FORMING MATERIAL WHICH IS RUPTURABLEUPON IMPACT AND WHICH CONTAINS AS A FINELY DISPERSED PHASE NUMEROUSCELLS OF A LIQUID VEHICLE, CARRYING DISSOLVED THEREIN A SUBSTITUTEDPHENOL HAVING SUBSTITUENT RADICALS SELECTED FROM THE GROUP CONSISTING OFA SINGLE SUBSTITUENT WHICH IS ONE OF THE ALKYL ALLYL, HALO,HALO-SUBSTITUTED ALKYL, CYCLOALKYL, PHENYL, HALOSUBSTITUTED PHENYL,ALKYL-SUBSTITUTED PHENYL, BIPHENYLYL, BENZYL, AND ALPHA-ALKYL-BENZYLRADICALS, OF ANY TWO SUBSTITUENT RADICALS AND OF ANY THREE SUBSTITUENTRADICALS INCLUDED AMONG SAID SINGLE SUBSTITUENTS EXCEPT WHEN TWO OF SAIDTWO OR THREE SUBSTITUENT RADICALS ARE IN THE 2,6-POSITIONS RELATIVE TOTHE PHENOLIC HYDROXYL GROUP, OF THE TETRAMETHYL AND TETRAHALO RADICALS,OF ANY OF SAID SUBSTITUENT RADICALS AND SAID GROUPS OF TWO, THREE ANDFOUR SUBSTITUENT RADICALS WITH A SECOND HYDROXYL RADICAL ALSO ON SAIDPHENOL, OF THE PARA-NITRO RADICAL, AND OF THE PENTAMETHYL AND PENTAHALORADICALS; SAID MANIFOLDING UNIT BEING ADAPTED TO PRODUCE A DARK COLOREDMATERIAL, UPON SAID IMPACT AND LOCAL RUPTURE OF SAID COATING WITHRELEASE OF SAID LIQUID VEHICLE INTO CONTACT WITH A CONTIGUOUS SURFACECARRYING A COLORLESS OR LIGHTLY COLORED CHROMOGENOUS COMPOUND WHICHINCLUDES AS ITS MAJOR FUNCTIONAL ARRANGEMENT THE MOLECULAR STRUCTURE